Aircraft Noise and Emissions Reduction Symposium (ANERS 2015)
The Impact of Multiple Runway Aiming Points on Runway Capacity Technical Capacity of a Single Runway
Niclas Dzikus Air Transportation Systems German Aerospace Center Hamburg, Germany
[email protected] Abstract—Environmental aspects of air transport are constraining factors for the present and future air transportation system. On the local scale, especially aircraft noise impacts the potential of traffic growth negatively. In order to reduce noise impact of aircraft operations around airports there are several technological and operational approaches. A promising measure to reduce aircraft noise is the adaption of approach procedures. A variety of concepts exist that aim at the adaption of the final approach trajectory, including the concept of multiple runway aiming points in which landing trajectories are optimized with respect to individual aircraft states and environmental conditions. By shifting the individual approach path, the noise carpet generated by the aircraft is shifted as close as possible to the airport0 s center. In this paper, an approach to assess the impact of multiple runway aiming points resulting from optimized aircraft landing trajectories on the technical capacity of a runway system is investigated. Therefore equations that allow for the calculation of separation times between the possible aircraft pairings as well as a simulation environment to determine technical hourly capacity of a single-runway system are introduced. For the presentation of the results, different scenarios to assess the impact of the concept of multiple runway aiming points on arrival capacity and on the capacity curve of a single-runway system are investigated.
from the physical threshold. As a result of both measures, the aircraft approaches the runway at higher altitudes and thereby noise impact can be reduced. ’Curved concepts’, enabled by satellite-based landing systems (e.g. Ground Based Landing Systems (GLS)), can be interpreted as revolutionary concepts compared to the aforementioned ones. Nevertheless, they have the potential to minimize aircraft noise significantly (see e.g. [4, 5]).
Keywords—air traffic management, multiple runway aiming points, adaptive runway aiming point, runway capacity, capacity envelope, separation, ground based landing system
I.
I NTRODUCTION
Air Traffic is expected to grow with a rate of ca. 5% per year until the year 2030 ([1]). There are certain challenges that will be confronted due to this growth in air transport ([3]). Climate change impacts the environment on a global scale whereas air quality and community noise are affected on a local scale. Because of its impact on human health ([2]) community noise often is a constraining factor for airport expansion and thus for air traffic growth in general. A variety of measures to reduce aircraft noise at its source (technological measures) or by abatement procedures (operational measures) are conceivable. An approach to classify a variety of possible operational measures to reduce noise impact during final approach is given in Fig.1. The first group, denoted as ’Glide Path concepts’ aim at an increase of the glide path angle. Therefore the touchdown point is not adapted in these cases. In contrast to these approaches, the ’Aiming Point concepts’ aim at shifting the touchdown point further away
Fig. 1. Classification of different operational measures that potentially reduce noise impact during final approach.
In this paper we focus on ’Aiming Point concepts’. The approach of a ’Displaced Threshold’ has already been investigated extensively in several projects. As an example the HALS/DTOP (High Approach Landing System/Dual Threshold Operation) project was conducted at Frankfurt Airport between 1994 and 2004 [6, 7]. The main objective was to increase arrival capacity by shifting the threshold of one of the parallel runways by 1500m. A similar approach is currently investigated at Zurich airport with satellite-based landing procedures. In both cases the airport can expect benefits with respect to its noise impact (see Fig.2). In contrast to the DTOP-approach, where the threshold is displaced by a specific distance (e.g. 1500m) the concept of ’Multiple Runway Aiming Points’ (MRAP) is based on landing trajectories which can be optimized for current aircraft states and conditions (e.g. aircraft type, aircraft weight, weather
Aircraft Noise and Emissions Reduction Symposium (ANERS 2015) conditions). On the basis of flight-specific input parameters, a trajectory is calculated that aims at shifting the touchdown point as far as possible to the selected runway exit. Thus, environmental benefit with respect to noise can be maximized. Because of individually assigned approach paths, the touchdown point and the corresponding threshold change dynamically. In this study, we investigate the extent to which runway capacity is impacted due to such a concept. We focus on the capacity of a single runway in the first instance.
Fig. 3. Decision tree for the calculation of separation times between a couple of arriving aircraft.
Fig. 2. Schematic diagram showing the effect of a displaced threshold on the noise footprint (adopted from [7]).
In chapter 2 the approach taken to determine separation times that ensure the necessary separation between arriving and departing aircraft is introduced. In chapter 3 a model chain is described that enables the calculation of hourly technical capacity of a single-runway system. Exemplary results are presented in chapter 4. The paper concludes with a summary of the results and gives an outlook for future enhancements of the model as well as the inclusion of more aspects for a holistic assessment of the technology in the airport and air transportation system. II.
C ALCULATION OF S EPARATION T IMES
As stated in the introduction the MRAP concept assigns an optimal landing trajectory for an arriving aircraft. We define threshold as a point within the approach trajectory of an aircraft where it crosses a specific height, e.g. 50ft. Therefore the threshold differs for every MRAP-capable aircraft. To meet the safety requirements, following rules apply: •
•
1st rule: Wake Vortex Separations (WVS) have to be kept and a are based on the threshold of the leading aircraft 2nd rule: Only one aircraft must be on the runway at a time
Based on this, a decision tree is developed which captures every possible combination of two arriving aircraft, independent of whether it is a conventional aircraft or MRAP-capable. The parameter ∆dof f set ([m]) represents the difference between the offset of the leading to the trailing aircraft. For a pairing of two conventional aircraft ∆dof f set is ’0’, accordingly. The case ∆dof f set > 0m constitutes the situation where the threshold of the leading aircraft is further than the threshold of the trailing aircraft with respect to the physical threshold. The variables vi and vj ([kts]) represent the approach speeds of the leading and the trailing aircraft, respectively.
For illustration ’case 2’ is described in more detail in the following. An example for this case might be a MRAP-capable aircraft that is followed by a conventional aircraft of wake vortex category ’medium’ (e.g. A320). The threshold of the MRAP-capable aircraft is further than the threshold of the trailing aircraft. This results in ∆dof f set > 0m. The approach speed of the leading aircraft is equal or less compared to the approach speed of the trailing aircraft, i.e. vi
